Impact of exogenous maltogenic α-amylase and maltotetraogenic amylase on sugar release in wheat bread

Effects of maltogenic α-amylase on physicochemical properties and edible quality of rice cake

Maltogenic α-amylase (MA) are commercially used in the baking industry to retard starch retrogradation. However, whether MA can be used to modify rice flour during the fermentation process to improve the quality of rice flour remains unclear. In this study, MA was introduced during rice cake (RC) processing, and the modification effect and underlying mechanism were explored. Mn showed a decreasing trend except for 4.0 × 10-3 U/g sample. Chain length distribution data showed that MA effectively hydrolyzed long chains in amylopectin and increased the concentration of amylopectin chain length with a degree of polymerization of ≤ 9. High-performance liquid chromatography results suggested that the maltose content increased to 3.14% at an MA concentration of 9.5 × 10-3 U/g, which affected the fermentation effect of MA-treated RC. MA effectively reduced the viscosity of RC, and the gelatinization enthalpy of RC changed to 0.835 mJ/mg. MA also reduced the hardness and chewiness of RC after storage for 7 d. Moreover, rapidly digestible starch and slowly digestible starch contents of MA-treated RC decreased and increased, respectively, and resistant starch contents were remained unchanged. These results indicate that MA exerts a significant and effective antiretrogradation effect on RC. Combining the above results with sensory evaluation findings, an MA concentration of 4.0 × 10-3 U/g was the best supplemental concentration for obtaining RC with better edible quality. These findings suggest that MA treatment to rice flour during the fermentation process not only preserved the edible quality of RC but also retarded its retrogradation, thus, providing a novel processing method for the industrial production of RC.

Influence of α-amylase, xylanase and cellulase on the rheological properties of bread dough enriched with oat bran

A better understanding of dough rheology during processing is crucial in the bakery industry, since quality attributes of the final product are influenced by those properties. In this study, we investigated the effects of xylanase, α-amylase and cellulase on the rheological properties of bread dough enriched in oat bran. A DoughLAB was used to measure the mixing characteristics of dough. According to the results, adding a single enzyme did not significantly affect the water absorption, development time, or stability of oat bran dough. In contrast, when blended enzymes were used at high concentrations (10, 120, and 60 ppm), the water absorption, development time, and stability of the oat bran dough were significantly reduced compared to using the single enzyme (62.1%, 7.1 and 6.6 min). It was found that combining α-amylase, xylanase and cellulase resulted in better extensibility and stickiness (16.5 mm and 60.8 g) of oat bran dough than using these enzymes individually. As a result, α-amylase, xylanase and cellulase complemented each other in determining the rheology of bread dough.